1. Field of the Invention
The present invention relates to videoarthroscopes.
2. Description of the Prior Art
The field of arthroscopic surgery has progressed rapidly. It has significantly changed the way in which orthopaedic surgeons treat a host of problems.
The earliest arthroscopes used an ocular lens and an eye shade through which the surgeon directly viewed the anatomy by looking into the ocular. As video cameras developed, they became practical for use with arthroscopes. Coupler systems for optically coupling the image from the arthroscope to a video camera were developed. Referring to FIG. 1, the early coupler systems included an arthroscope 2, a coupler 4 and a camera housing 6. The assemblies tended to be relatively bulky and cumbersome. Maneuverability was difficult.
An improved coupler which overcame some of those problems is described in Prenovitz et al., U.S. Pat. No. 4,611,888. The Prenovitz coupler consists of two sections rotatable with respect to one another. The front section of the coupler is nonrotatably mounted to the proximal end of an arthroscope. The rear section of the coupler is nonrotatably mounted to the distal end of a video camera. Rotation of the arthroscope image with respect to the camera is effected by rotating the front section of the coupler with respect to its rear section. Because of the two-piece construction of the coupler, seals are needed between the arthroscope and the front section of the coupler, between the rear section of the coupler and the camera, and between the front and rear sections of the coupler itself.
Other patents relating to video arthroscopes include Watanabe, U.S. Pat. Nos. 4,590,923 and 4,756,304.
Later, videoarthroscopes were developed which combine the functions of the arthroscope and the coupler, as shown in FIG. 2. The videoarthroscope 8 attaches directly to the camera housing 15.
During arthroscopic surgery, the surgeon uses one hand to remove, repair or dress tissue with instruments such as probes, knives, forceps and cutters. With the other hand, the surgeon holds the videoarthroscope. Arthroscopes can be focused to accommodate changes in the distance of the observed surface. The angular needle of the arthroscope can also be rotated about its longitudinal axis to scan the operative area and thereby increase the field of view. The focusing and rotation adjustments are critical.
The size and configuration of the arthroscope-coupler-camera assemblies and videoarthroscopes have, heretofore, required the surgeon to use two hands to make those critical adjustments. The prior art devices are relatively long (FIGS. 1, 2 and 3 are drawn to full scale) and have a high degree of rotational stiffness in their focusing and rotation means. Thus, they cannot be held in one's hand and adjusted with the fingers of that same hand. In order to make the necessary adjustments, the surgeon must let go of the cutting or probing instrument to free both hands for maneuvering the videoarthroscope. He must then reposition the cutting or probing instrument to resume the procedure. The practice is not only time consuming but lends itself to error.
There is a need for a videoarthroscope which can be held and maneuvered with one hand. An object of the present invention is to provide a videoarthroscope which permits one handed control.